A Turnigy 9x is a great entry-level aftermarket controller, but you will need to replace the Phantom's Rx with the one that came with the 9x, or get a Tx module for the back of the 9x and a matching Rx (such as FrSky).

Are you already looking at a particular 9x..new or used?

For reference, a FrSky Tx module would cost around $30 on top of the price of the 9X, and the Rx would be in the $25-$30 range depending on which FrSky model you choose. Let me know if you want some more input on those options, I still keep my 9X around as backup

And, for a bit (but not much) more than that, you could just get a FrSky Taranis with matching Rx. Excellent controller, but that would push total cost to around $200.

Great information there. Thanks much.
$200 is better than $500 at this point. I've been buying a bunch of stuff to get my bare bones P2 up to where I want it to be. I need to chill out before I go out and buy a new or used controller right now. In a few weeks, I'll see if anyone has a good radio. For now I read I can get a lever to add to my stock P2 radio. I might temporary do that.

By the way.... If I came across a Futaba 14SG for a good price, would that work directly with the P2 receiver or would I need the receiver that came with it? Would any FASST radio work with the P2 receiver? In airplane or helicopter mode?
Thanks all.